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5 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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CS3352 Information Retrieval, Hypermedia and the Web
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Web 2.0

Sean Bechhofer

School of Computer Science,

University of Manchester, UK

CS3352

CS3352 Information Retrieval, Hypermedia and the Web
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Things to think about


How would we use Semantic Web technology to help us build
Web 2.0 applications?


How would I change my information delivery mechanisms to
make my data/content more amenable to Web 2.0?

CS3352 Information Retrieval, Hypermedia and the Web
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Web 2.0


What was Web 1.0?


What is Web 2.0?


Is it the same as Semantic Web?


If not, is it better than Semantic Web?


Is it Web Services?


If not, is it better than Web Services?


How will we do it?


What are the technologies/methodologies?



CS3352 Information Retrieval, Hypermedia and the Web
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flickr

Google Maps

blogging

folksonomy

RSS

Wikis

Wikipedia

BitTorrent

Web Services

Collective Intelligence

tagging

del.icio.us

What is Web 2.0?

mashups

AJAX

the long tail

rich user experiences

micro
-
pages

services not software

participation not publishing

emergence

ebay

skype

CS3352 Information Retrieval, Hypermedia and the Web
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What is Web 2.0?


“Web 2.0” is a term used to describe an emerging collections of
technologies, approaches and principles.


Perhaps already somewhat overused and hyped


What is it that allows us to identify and characterise an
application or an approach as Web 2.0?


The answer to this is not cut and dried. Applications and companies
claiming to be Web 2.0 are not, while others that make no claim
are.

CS3352 Information Retrieval, Hypermedia and the Web
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Tim O’Reilly on Web 2.0


A recent essay by Tim O’Reilly sets out many of the
characteristics of Web 2.0.







In the article, he describes seven principles of Web 2.0


Much of the following content will be based on these
observations.

What is Web 2.0

Design Patterns and Business Models for
the Next Generation of Software

http://www.oreillynet.com/pub/a/oreilly/tim/news/2005/09/30/what
-
is
-
web
-
20.html

CS3352 Information Retrieval, Hypermedia and the Web
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[O’Reilly 05]

CS3352 Information Retrieval, Hypermedia and the Web
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O’Reilly’s Principles

1.
Web as Platform

2.
Harnessing Collective Intelligence

3.
Data is the Next Intel Inside

4.
End of the Software Release Cycle

5.
Lightweight Programming Models

6.
Software Above the Level of a Single Device

7.
Rich User Experience



CS3352 Information Retrieval, Hypermedia and the Web
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1. Web as Platform


Loosely Coupled Components


Bound together via web protocols and standards


Software as services


Services as building blocks for other services


CS3352 Information Retrieval, Hypermedia and the Web
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2. Harnessing Collective Intelligence


Successful Web 2.0 applications make use of, and exploit the
notions of collective intelligence


Social Bookmarking


Tagging


Wikis


“If you liked that, you’ll like this”


Collaborative filtering

CS3352 Information Retrieval, Hypermedia and the Web
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The Network Effect


Goods or services that increase in value depending on the
number of people owning or using that service.


E.g. Telephones


If there are only two people in the world with telephones, the
telephone is not that useful.


If there are 1 billion telephones, then the telephone is useful.


Similarly for sites such as eBay.


More buyers leads to more competition for items and higher prices.


Higher prices attracts sellers, introduces competition and drives
prices down.


Social networking sites (e.g. LinkedIn)


The more people using the site, the more useful it becomes.

CS3352 Information Retrieval, Hypermedia and the Web
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Network Effects


Getting information or value into applications can be hard


Pay people


Get volunteers


???


Make it as easy as possible to aggregate user data as a side
-
effect of them using your application


E.g. flickr


Photos, tags etc.
default

to public


Network Effects by Default


O’Reilly design principle

CS3352 Information Retrieval, Hypermedia and the Web
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The Intelligence Landscape

Artificial Intelligence

Lots

Not
much

Not
much

Lots

Collective Intelligence

Ontology
Building

Semantic
Web
Services

FOAF

RSS

OWL

RDF

Knowledge

Discovery

SWRL

Information
linking

Social
bookmarking

Flexible &
extensible

Metadata

schemas

Decision making

Web

CS3352 Information Retrieval, Hypermedia and the Web
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Evolution towards Read/Write Web

Web 2.0
: Web pages plus other
content, shared (interactively) over
the web. More like an application
than a page

Web 1.0
: HTML pages
served up then viewed
using a browser


Read



Write & Contribute

Page



Post

Static



Dynamic

Web Browser



Browser, RSS Reader, App

Client/Server



Web Services

Web Coders



Everyone

Geeks



Mass Amateurisation

Consumer as Producer

CS3352 Information Retrieval, Hypermedia and the Web
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Wikis


Simple, collaborative mechanism for building and maintaining
web pages.


Wikipedia perhaps the best known example


But…


Needs some organisational structure


May also need editorial control


“Just who would want to vandalise

an entry on cheese?”


Semantic Wikis


Using SW technologies to help

organise and search through wiki

contents.

CS3352 Information Retrieval, Hypermedia and the Web
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Folksonomies


Used in sites like
flickr

or
del.icio.us

and in general in social
networking applications


Provide an unrestricted way of building a vocabulary.


Lightweight, quick and easy


Little constraint on users (thus popular)

A collaborative but unsophisticated way in which
information is being categorized on the web. Instead of
using a centralized form of classification, users are
encouraged to assign freely chosen keywords (called tags)
to pieces of information or data, a process known as
tagging.

CS3352 Information Retrieval, Hypermedia and the Web
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Folksonomies


Folksonomies may provide a nice quick way to produce
lightweight, flat collections of keywords, but are less likely to
help produce detailed ontologies.


Ok if you’re
browsing

(e.g. photo libraries), but what about
directed searching
?



Tom Gruber’s “ontology of folksonomy”


http://tomgruber.org/writing/ontology
-
of
-
folksonomy.htm



Introducing some structure to the tagging process

CS3352 Information Retrieval, Hypermedia and the Web
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RSS


Really Simple Syndication


Lightweight standard


Allows publication of content feeds


Linking to resources, with notifications of page changes.


Dynamic linking


Pub/Sub


“The most significant advance in the fundamental
architecture of the web since […] CGI.”


O’Reilly

CS3352 Information Retrieval, Hypermedia and the Web
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<?xml version="1.0" encoding="utf
-
8"?>

<rss version="2.0" xmlns:media="http://search.yahoo.com/mrss">


<channel>


<title>guitarfish's Photos</title>


<link>http://www.flickr.com/photos/guitarfish/</link>


<description>A feed of guitarfish's Photos</description>


<pubDate>Thu, 27 Apr 2006 10:04:51
-
0800</pubDate>


<lastBuildDate>Thu, 27 Apr 2006 10:04:51
-
0800</lastBuildDate>


<generator>http://www.flickr.com/</generator>


<image>


<url>http://static.flickr.com/49/buddyicons/66243365@N00.jpg?1145894649</url>


<title>guitarfish's Photos</title>


<link>http://www.flickr.com/photos/guitarfish/</link>


</image>



<item>


<title>Drink Beer!</title>


<link>http://www.flickr.com/photos/guitarfish/135976102/</link>


<description>guitarfish posted a photo:...</description>


<pubDate>Thu, 27 Apr 2006 10:04:51
-
0800</pubDate>


<author>nobody@flickr.com (guitarfish)</author>


<guid isPermaLink="false">tag:flickr.com,2004:/photo/135976102</guid>


<media:content url="http://static.flickr.com/50/135976102_b29b452f0a_o.jpg"


type="image/jpeg"


height="576"


width="768"/>


<media:title>Drink Beer!</media:title>


<media:text type="html">...</media:text>


<media:thumbnail url="http://static.flickr.com/50/135976102_b29b452f0a_s.jpg" height="75" width="75"/>


<media:credit role="photographer">guitarfish</media:credit>


<media:category scheme="urn:flickr:tags">beer japan</media:category>


</item>


<item>…</item>


</channel>

</rss>


CS3352 Information Retrieval, Hypermedia and the Web
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RSS


RSS feeds describe items


Title, Description, Link, Publication date etc.


RSS aggregation originally through web
-
browser.


Now a wide variety of applications


Web Browser


Desktop


Mobile Device


Alternatives exists, e.g. Atom, TPEG (Transport Protocol
Experts Group)


CS3352 Information Retrieval, Hypermedia and the Web
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Feeds


Feeds now supply a huge variety of content and data updates:


Stock quotes


Weather data


TV and Radio schedules


Travel information


See, for example the BBC’s backstage initiative:


http://backstage.bbc.co.uk/



Content feeds provided for developers to build novel applications
based on BBC content (see
Mashups
).


CS3352 Information Retrieval, Hypermedia and the Web
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3. Data is the next Intel Inside


Successful Internet applications have been backed by
specialised databases


Google, Amazon, Yahoo!, eBay, Napster


Who owns this data?


Without ownership, it’s easy for competitors to enter the market
and offer competing applications simply by licensing the same
data.


E.g. MapQuest quickly overtaken by Yahoo!, Microsoft and now
Google.

CS3352 Information Retrieval, Hypermedia and the Web
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Enhanced Data


Amazon took original ISBN database and enhanced it


Information from publishers


Information from users (reviews, comments etc)


Relies on it being
easy

to add value to the users


Cf. Network Effects


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4. End of the Software Release
Cycle


Web 2.0 software is delivered as services, not as a product.


Maintenance becomes crucial


Refining services


Google continually updating/crawling


Users as co
-
developers


Open Source philosophies


Release early, release often


Collective debugging


Close monitoring of features.


Participation

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5. Lightweight Programming


Loosely coupled systems


Web Services (cf. Mark Little’s lecture)


Moving away from heavyweight APIs: CORBA, RMI etc.


Implementation independence


Syndication rather than coordination


Pushing data out


Don’t care what then happens


Reuse and Remix


Creating novel applications through assembly



CS3352 Information Retrieval, Hypermedia and the Web
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Mashups


Applications that take information from multiple sources and
merge it, providing added value


Many mashups make use of the Google Maps API or Google
Earth


Combining BBC Travel feeds with Google Maps to show real time
traffic problems


http://bbc.blueghost.co.uk



Geographical locations featuring on TV:


http://tvmap.thomasscott.net/



Good news/Bad news classification


http://www.latedecember.com/sites/moodnews/index.html



Overlaying multiple sites onto Google Maps,


http://www.dynamite.co.uk/local/


Flickr Sudoku!


http://flickrsudoku.com/default.aspx


CS3352 Information Retrieval, Hypermedia and the Web
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Mashups


Key here is content/data provided via services


Not just screen scraping


What about metadata?


Lots of different data


Geographical locations


Descriptions


Tags


Authors


How do I know what this stuff is all about?


How do I know which things I should be combining?


2.75 new mashups every day


http://www.mashupfeed.com/


CS3352 Information Retrieval, Hypermedia and the Web
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7. Rich User Experience


JavaScript and DHTML provided rich client side programming in
a lightweight fashion.


AJAX (Asynchronous Javascript + XML)


Term coined

by Jesse James Garrett of Adaptive Path


Standards
-
based

presentation using
XHTML

and
CSS
;


Dynamic

display and interaction using the
Document Object Model
;


Data
interchange

and
manipulation

using
XML

and
XSLT
;


Asynchronous

data retrieval using
XMLHttpRequest
;


JavaScript

binding everything together.



CS3352 Information Retrieval, Hypermedia and the Web
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AJAX

[Garrett 05]

CS3352 Information Retrieval, Hypermedia and the Web
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AJAX


AJAX engine takes care of interaction with the server and
rendering content for the user.


Asynchronous communication with the server


No waiting for pages to load


Smoother User Experience


Examples


Google Suggest


Providing suggestions as you type.


Google Maps


Pan, Zoom, Expand


flickr


Move away from Flash to AJAX
-
based implementations


Open and standards based.

CS3352 Information Retrieval, Hypermedia and the Web
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Friend or Foe?


Web 2.0
,
Semantic Web

and

Web Services

should not be seen

as
competing

technologies or

approaches.


Rather they are
complementary


Web Services are key to delivering

information and services in a loosely coupled way, and allow
flexible repurposing of content.


Semantics (both rich and lightweight) are needed to
describe

our resources in order to facilitate reuse.

CS3352 Information Retrieval, Hypermedia and the Web
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Things to think about (reprise)


How would we use Semantic Web technology to help us build
Web 2.0 applications?


How would I change my information delivery mechanisms to
make my data/content more amenable to Web 2.0?

CS3352 Information Retrieval, Hypermedia and the Web
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Next Week


Revision clinic with Carole on the 12th.


Keep an eye on the newsgroup for any further announcements!